This Center for the Study of Reproduction will support a multidepartmental, interdisciplinary group of 31 faculty who are working jointly on research problems related to mammalian reproductive biology. The faculty has successfully blended its training and investigative efforts over the past twenty years, and has gained collective recognition for excellence of reproductive research. This renewal request seeks funds to maintain and strengthen existing core facilities and add an additional core focused on molecular biology. These core facilities provide the framework for the Center. The requested support is for the following core facilities: Core A: Administration; Core B, Data Analysis and Computing; Core C, Laboratory Animal; Core D, Molecular Biology; Core E, Morphology; Core F, Sheep; and Core G, Standards and Reagents. These core facilities will support clinical and basic science faculty who are studying pulsatile patterns of hormone secretion; the regulation of gene expression in reproductive tissues; development and function of pituitary, ovarian, testicular, mammary and uterine tissues in vitro and in vivo; the mechanisms of hormone action; the mechanisms by which neuroendocrine systems control reproduction; the influence of photoperiodic rhythms, exercise and nutrition on reproductive behavior and physiology; and the development of new, non-radioisotopic assays.